Alert archive / Maryland / Mesoscale Discussions in 2016

Mesoscale Discussion 345

April 7, 20164 states

The Storm Prediction Center issued this mesoscale discussion at Apr 7, 2016, 11:36 AM EDT for 4 states. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued
Apr 7, 2016, 11:36 AM EDT (15:36 UTC)
Expired
Apr 7, 2016, 1:30 PM EDT
In force
114 min
Issued by
the Storm Prediction Center
Chance of a watch
5%

Counties Kent County, DE, New Castle County, DE, Sussex County, DE, Caroline County, MD, Cecil County, MD, Dorchester County, MD, Kent County, MD, Queen Anne's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Worcester County, MD, Atlantic County, NJ, Cape May County, NJ, Cumberland County, NJ, Salem County, NJ, Accomack County, VA

The radar

The Dover AFB radar (KDOX), 26 km from the middle of the area, began a volume at 15:39 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 3.6 hours before the alert went out and 79 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Wallops Is Stn, VA at 12:00Z on 2016-04-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 12:00Z on 2016-04-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 268 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
710 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
268 m²/s²
0-3 km storm-relative helicity
289 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

134 
ACUS11 KWNS 071537
SWOMCD
SPC MCD 071536 
NJZ000-MDZ000-DEZ000-VAZ000-071730-

MESOSCALE DISCUSSION 0345
NWS STORM PREDICTION CENTER NORMAN OK
1036 AM CDT THU APR 07 2016

AREAS AFFECTED...DELMARVA TO SOUTHERN NJ

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 071536Z - 071730Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A STRONG WIND GUST CANNOT BE RULED OUT AS BANDS OF SHOWERS
ADVANCE TO THE EAST-NORTHEAST ACROSS THE DELMARVA PENINSULA AND
SOUTHERN NJ THROUGH 18Z...WHEN THIS CONVECTION SHOULD THEN MOVE
OFFSHORE.

DISCUSSION...AT 1515Z...MOSAIC RADAR IMAGERY AND INDIVIDUAL WSR-88D
SITES IN THE SOUTHEAST PA/MD AND DELMARVA AREA SHOWED LOW-TOPPED
BANDS OF SHOWERS EXTENDING FROM SOUTHEAST PA TO EASTERN MD WITH THE
LATTER AREA HAVING SHOWERS RECENTLY MOVING ONSHORE FROM THE
CHESAPEAKE BAY.  DESPITE VERY WEAK INSTABILITY AND WEAK DEEP-LAYER
LAPSE RATES ACROSS THIS REGION...STRONG FORCING MECHANISMS ACROSS
THE MID-ATLANTIC STATES ATTENDANT TO 1/ A COMPACT SHORTWAVE TROUGH
AND 2/ WITHIN THE EXIT REGION OF A STRONG MID-UPPER LEVEL JET MAX
MOVING THOUGH THE TN VALLEY ARE SUPPORTING THE LINEAR STRUCTURES. 
THE WEAK BUOYANCY WITH EASTWARD EXTENT WILL CONTINUE TO LIMIT
PARCELS FROM REACHING TEMPERATURES COLD ENOUGH FOR CHARGE SEPARATION
AND TEND TO INHIBIT THE OVERALL STRENGTH OF THE SHOWERS.  THE BANDS
OF SHOWERS ARE MOVING TO THE EAST-NORTHEAST AT 35-40 KT...AND GIVEN
THESE SPEEDS A STRONG WIND GUST OR TWO MAY REACH THE SURFACE...
THOUGH THE OVERALL WEAK SURFACE-3 KM LAPSE RATES SUGGEST THE
COVERAGE OF THIS THREAT WILL BE VERY LOW.

..PETERS/HART.. 04/07/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PHI...AKQ...LWX...

LAT...LON   37827622 38477618 38967620 39417644 39577607 39647579
            39717518 39717445 39567406 38857470 38297499 37787528
            37467564 37427598 37487614 37827622

Nearby

Mesoscale Discussions in Maryland, 2016Mesoscale Discussions in New Jersey, 2016Mesoscale Discussions in Delaware, 2016Every mesoscale discussion in 2016

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.